Increase in background stratospheric aerosol observed with lidar at Mauna Loa Observatory and Boulder, Colorado
Article first published online: 4 AUG 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 15, 16 August 2009
How to Cite
2009), Increase in background stratospheric aerosol observed with lidar at Mauna Loa Observatory and Boulder, Colorado, Geophys. Res. Lett., 36, L15808, doi:10.1029/2009GL039008., , , , and (
- Issue published online: 4 AUG 2009
- Article first published online: 4 AUG 2009
- Manuscript Accepted: 6 JUL 2009
- Manuscript Revised: 24 JUN 2009
- Manuscript Received: 27 MAY 2009
- stratospheric aerosol;
- sulfur dioxide emissions;
- coal consumption
 The stratospheric aerosol layer has been monitored with lidars at Mauna Loa Observatory in Hawaii and Boulder in Colorado since 1975 and 2000, respectively. Following the Pinatubo volcanic eruption in June 1991, the global stratosphere has not been perturbed by a major volcanic eruption providing an unprecedented opportunity to study the background aerosol. Since about 2000, an increase of 4–7% per year in the aerosol backscatter in the altitude range 20–30 km has been detected at both Mauna Loa and Boulder. This increase is superimposed on a seasonal cycle with a winter maximum that is modulated by the quasi-biennial oscillation (QBO) in tropical winds. Of the three major causes for a stratospheric aerosol increase: volcanic emissions to the stratosphere, increased tropical upwelling, and an increase in anthropogenic sulfur gas emissions in the troposphere, it appears that a large increase in coal burning since 2002, mainly in China, is the likely source of sulfur dioxide that ultimately ends up as the sulfate aerosol responsible for the increased backscatter from the stratospheric aerosol layer. The results are consistent with 0.6–0.8% of tropospheric sulfur entering the stratosphere.